Boiler feed water regulator and like apparatus for regulating liquid levels



S. R. DIGHT BOILER FEED WATER REGULATOR AND LIKE APPARATUS FORREGULATING LIQUID LEVELS 3 Sheets-Sheet 1 Filed May 19, 1934 Inventor J.19 Eight.

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Oct. 1, 1935. s. R. DIGHT BOILER FEED WATER REGULATOR AND LIKE APPARATUSFOR REGULATING LIQUID LEVELS Filed May 19, 1934 3 Sheets-Sheet 2 4 4Q mF u /N W& $1 7 I, 4 L l R I. m R d 16W. v F

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BOILER FEED WATER REGULATOR AND LIKE APPARATUS FOR REGULATING LIQUIDLEVELS Filed May 19, 1934 3 Sheets-Sheet 3 V Irwntor W- z W.

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Patented Oct. 1, 1935 UNITED STATES BOILER FEED WAT ER REGULATOR ANDLIKE APPARATUS FOR REGULATING LIQUID LEVELS Sydney Rupert Dight, Haslar,Gosport, England,

assignor to G. Scotland 8}: J. Weir, Limited, Glasgow,

Application May 19, 1934, Serial No. 726,523 In Great Britain March 21,1933 6 Claims.

This invention relates to apparatus for the automatic regulation of thesupply of liquid for the maintenance of a substantially constant levelof liquid in a container, such for example, as a steam boiler from whichthe liquid is drawn off either as vapour or liquid, and is moreparticularly applicable to such apparatus comprising a pump systemserving to feed liquid from a supply tank or reservoir to the Workingcontainer in which the constant level of liquid is to be maintainedunder the control of a float or the equivalent. An example of the typeof apparatus to which the invention relates is a feed water system forsteam generator plants in which leakage of water from beneath a feedvalve past a connected and leaking piston into a chamber beneath thepiston is controlled by a valve operated by a float in a chamber whichis in free communication with the steam boiler or which is providedwithin the boiler, whereby as the level within the boiler falls thefloat-operated valve stops or reduces the flow of leakage water frombeneath the piston so that the pressure on the feed valve builds upuntil it is sufiicient to open the feed valve against the pressurewithin the boiler and to allow feed water to be pumped into the boiler.Such a feed water system is described in detail in the specification ofapplication for patent Serial No. 590,668, now Patent No. 1,980,749issued Nov. 13, 1934.

The invention has among its objects to provide a feed valve which isespecially sensitive and smooth in its operation, to provide for thereturn of the leakage water into the closed feed water system withoutnecessarily passing by way of the feed tank and through the pump, toensure that the minimum pressure acting on the piston is that existingin the container and generally to improve the operation and constructionof such apparatus.

According to the invention the feed valve is subjected to the pressureof the feed acting in opposite directions on surfaces of different area,and the resulting differential pressure is operative in efiecting themovement of the valve to establish and control the feed.

According to the invention, moreover, the feed valve may be subjected inthe one direction to the action of the feed pressure, and in theopposite direction to the action of the boiler pressure and the feedpressure distributed over differing areas so that movement of the valveis determined by the surplus or differential pressure of the feedsupply.

According to the invention, moreover, the feed tainer,

pressure which is applied to the surface of smaller area of the feedvalve may be rendered effective to operate upon the feed-valve by meansof a piston and cylinder, of which either the piston or the cylinder maybe in fixed relation to the feed valve and may co-operate with acylinder or piston in fixed relation to the valve casing.

According to the invention, also, the resultant total effective pressureacting upon the feed valve is determined by a control device operated bya float or the equivalent in such manner that the valve is opened orclosed according to the level of liquid in the container.

According to the invention, moreover, in its application to a feed watersupply system of the type described which operates as a closed feedsystem, the leakage liquid passing from the feed to the chamber orclearance space below the valve-operating piston is discharged into thecontainer or into the float chamber or other vessel connected with thesaid container, and for this purpose the control valve operated by thefloat may be provided to afford a passageway for the leakage liquid intothe said container or float chamber.

25 According to the invention, moreover, a nonreturn valve may beprovided at a position in the pipe line connecting the feed valve andthe control device controlling the flow of leakage water from the feed,so that in the case of loss of feed pressure due, for example, to thebreakage of a pipe or the stoppage of a pump the feed valve remainsclosed under the pressure in the conwhich is thus prevented from passingto the feed pipe line.

35 The invention further comprises the features hereinafter describedand claimed.

The invention is illustrated by way of example in the accompanyingdiagrammatic drawings.

Figure 1 illustrates a boiler feed regulator provided in accordance withthe invention, in part sectional elevation.

Figure 2 is a detail View to an enlarged scale of the float-operatedvalve, together with a sectional view of its casing.

45 Figure 3 is a cross-section taken in Figure 2 on the line 3-3.

Figure 4 is a sectional elevation illustrating a modified constructionof the feed valve and its casing.

50 Figures 5 and 6 are further modifications of construction of the feedvalve and the part of the casing with which it co-operates.

In carrying the invention into efi'ect as illustrated in Figures 1 to 3of the drawings, which show a boiler feed water regulator and feedsystem of the type hereinbefore described and referred to in thespecification of application for patent Serial No. 590,668, now PatentNo. 1,980,749, issued Nov. 13, 1934, the feed check valve a hasconnected to it'a piston b adapted to have sufficient clearance to workfreely within the cylinder 0 forming part of the valve casing and sothat leakage results through a substantially constant area past theperiphery of the piston. The delivery from the feed pump enters thevalve casing at d between the valve a, and piston 13. The chamber orclearance space 0 beneath the piston b is connected through a non-returnvalve f by the pipe c with the casing m of a float-operated controlvalve Z. The valve (1 is advantageously provided with a skirting a ofconed or tapering form such that the area of opening on the rising ofthe valve gradually increases and thus contributes to the sensitivecontrol of the valve.

According to the invention the piston 17, is provided on its upper facewith a cylindrical extension forming a piston a which is adapted tooperate within a cylinder 0 formed as a downwardly extending boss uponthe cover plate 0 of the feed valve casing. Communication between thefeed supply at d and the interior of the cylinder'c is effected by apassage a provided in the piston a and its rod. A spindle s may beprovided mounted within a stuffing box 0 provided in the cover plate (2and may be adapted to be screwed down by means of a hand wheel or otheradjusting means for the purpose of bringing the enlarged head 8 into adetermined position of adjustment whereby it may limit the maximumopening of the feed valve or when it is desired to shut off the feed,into a position in which it maintains the feed valve (1 upon its seatand also closes the passage 09, the non-return valve 1 being also closedto prevent leakage of water into the boiler or container.

The casing m of the control valve 1 is mounted upon the float casingh-which is preferably disposed close to the steam and water drum of theboiler and being in communication respectively at its upper and lowerends with the upper and lower parts of the drum by means of connection1' and J. The float k is mounted upon a counterbalanced float lever kpivotally carried on a bracket 71 secured to and depending from thefloat casing cover plate 71?. r a

The valve Z is mounted at the upper end of a vertically disposed spindleZ axially movable within a sleeve or casing l which is mounted by meansof a screw thread upon the cover plate It and enclosed within the valvecasing m. Thelower end of the spindle Z is connected to the float leverby a link 1 so that variations in the positions of the float k dependentupon variation in level of the water in the float chamber it causecorresponding movements of the float-operated control valve 1.

This valve is advantageously formed at its upper end of a substantiallytapering or pointed form and is adapted to co-operate with the centralbore p of a valve bush 1? which is carried by a spindle 11 so that itsposition in relation to the sleeve or casing I may be adjusted. The pipee is connected to the valve casing m at a position above the valve bushp and communication with the bore p of the valve bush is effectedthrough suitable oriflces or other openings provided in the supportingmember by which the valve bush is carried from the spindle'p A pipe nconnects with the valve casing m at a position below the valve bush pand at its far end is connected to the delivery or boiler side of thefeed valve casing 0.

" piston b the piston 12 may also be provided with leakage passages 0, oto co-operate with a throttle l0 valve q in the manner described in thespeoifica-- tion of the application Serial No. 590,668, now Patent No.1,980,749, issued Nov. 13, 1934.

It will be understood that when the valve a is in the closed positionand no feed is required or being 15 effected, apart from the leakagepast the piston b, which is' a negligible quantity, the pressure of thefeed is substantially balanced in its action upon the upper surface ofthe piston b and upon the under surface of the valve a and since the 20chamber 0 is in communication through the'nonreturn valve 1 and thefloat valve casing m with the boiler or float casing n no pressure abovefeed pressure or above boiler pressure tends to be established below thepiston 17, while the passage a permits the feed pressure to be appliedin the opposed direction upon the piston a and such pressure issupplemented by the boiler pressure acting upon the annular surface a ofthe valve a, which surface may have an area the piston 11?. There istherefore a' pressure acting upon the valve a to maintain it closed.When the level of liquid in the float casing it falls the verticalspindle Z is lifted by the float k and causes the valve Z to throttle orclose the bore of the valve 35 the boiler pressure acting on the surfacea of the 45 a valve or is established and'the valve a is smoothly .andsensitively lifted without shock or hunting to the extent necessary topermit the admission of the feed water to the boiler to re-establish thelevel of water therein. While the level of liquid 50 is beingre-established in the float'casing h the valve Z is being withdrawn fromthe valve bush 1) 7 so that the passageway for leakage water from thechamber 0 is gradually rendered operative again. It will be understoodthat by reason of 55 the conditions under which the valve a is operatedand the fact that a relatively small differential pressure is requiredto move it, and furthermore owing'to the fact that the piston a workingin the cylinder 0 operates as a dash-pot 60 to damp any tendency to ajerky movement of the valve a the feed is effected in a particularlysmooth and sensitive manner, without hunting of the valve and withoutshock, and so that a small 7 difference in the level of liquid in theboiler is at 65 once operative through the control valve to effect 7 acorresponding feed.

' ter which is hot feed water is led into the boile 75 for liquid fromthe 5 twice that of ac 1 instead of being returned to the feed tank orfeed system. There may thus be secured economy in weight andsimplification of the mechanism in View or" the reduction in the numberof pipes and connections required and the small size necessitated forthe moving valve parts.

The fact that the leakage from the chamber 0 and the cylinder 0, is fedinto the fioat casing or into the boiler renders important the provisionof the non-return valve 1 so that in the event of an interruption in thefeed supply whereby the pressure of the feed is lowered or destroyed,the boiler pressure may not be rendered operative to lift the valve orand permit a discharge from the boiler through the feed by Way of thefeed system.

It will be understood that it is immaterial whether the feed valve isrendered rigid with the piston or with the cylinder by which thepressure of the feed is applied to close the valve. Figure l illustratesa modified construction of the apparatus according to the invention inwhich the valve at is formed in fixed relation with the piston a whilethe cylinder 0 is integral with or carried by the cover plate 0 of thevalve casing c. As illustrated, the passage (2 may be provided with ascrew-threaded recess a for a calibrated bush in order that the deliveryof the feed liquid into the cylinder 0 may be determined.

Figure 5 illustrates a construction of the valve a in which it is formedintegral with the cylinder a while the piston c is mounted upon thecover plate 0 and is recessed to receive the head of the spindle s.

In Figure 6 a similar construction of the valve a and cylinder a isillustrated, but in this case the piston is entirely formed by the head8 of the spindle s.

It will thus be understood that the invention is not limited toparticular constructional details and that these may be varied withinthe scope of the claims hereinafter set forth. Thus, the relativediameters of the operating piston and the feed valve may be variedaccording to the conditions under which the feed system is required tooperate.

I claim:-

1. Apparatus for automatically regulating the feed of liquid into acontainer for the maintenance of a substantially constant level ofliquid in the container, comprising a casing having a liquid feed inlet,a feed inlet valve exposed on one side to pressure from the liquidsource and on its opposite side to pressure from the container and whichtends to close under the pressure from the container, a piston in fixedrelation to said feed inlet valve and exposed on one side to pressurefrom the source, a chamber in said casing in which the said pistonmoves, said chamber being normally in communication with the liquidsource through the space in which the piston moves whereby feed pressureis caused to build up in said chamber to act on the opposite side of thepiston, a fioat-operated valve responsive to the variations of the levelof liquid in the container, a passage connecting said chamber with saidfloat-operated valve, said float-operated valve controlling the buildingup of feed pressure within the said chamber, and an auxiliary piston andcylinder in said casing, one element of which is in fixed relation tothe feed inlet valve, said cylinder being normally in free communicationdirectly with the feed inlet for the building up of the feed pressuretherein coacting with the pressure from the container on the feed valveto tend to close the feed valve.

2. Apparatus for automatically regulating the feed of liquid into acontainer for the main tenance of a substantially constant level ofliquid in the container, according to claim 1, wherein the feed liquidenters the chamber by leakage past the piston and the leakage liquid isdischarged under the control or" the float-operated valve into thecontainer.

3. Apparatus for automatically regulating the feed of liquid .into acontainer for the maintenance of a substantially constant level ofliquid in the container, according toclaim 1, wherein the feed liquidenters the chamber by leakage through the piston and the leakage liquidis discharged under the control of the float-operated valve into avessel connected with the said container.

4. Apparatus for automatically regulating the feed of liquid into acontainer for the maintenance of a substantially constant level ofliquid in the container, according to claim 1, wherein the feed liquidenters the chamber by leakage past the piston and the leakage liquid isdischarged by a by-pass passage in the float-operated control valve tothe container.

5. Apparatus for automatically regulating the feed of liquid into acontainer for the maintenance of a substantially constant level ofliquid in the container, according to claim 1, wherein the feed liquidenters the chamber by leakage past the piston and the float-operatedvalve is provided with a casing connected with the container for thedischarge of the leakage liquid into the container.

50 6. Apparatus for automatically regulating the feed of liquid into acontainer for the maintenance of a substantially constant level ofliquid in the container, according to claim 1, wherein the passageconnecting the chamber with the float-operated valve is provided with anon-return valve.

SYDNEY RUPERT DIGI-IT.

